/*
 * Copyright 2002-2014 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package qunar.tc.bistoury.instrument.client.spring.el;

import java.math.BigDecimal;
import java.math.BigInteger;

/**
 * The power operator.
 *
 * @author Andy Clement
 * @author Giovanni Dall'Oglio Risso
 * @since 3.0
 */
class OperatorPower extends Operator {

    public OperatorPower(int pos, SpelNodeImpl... operands) {
        super("^", pos, operands);
    }


    @Override
    public TypedValue getValueInternal(ExpressionState state) throws EvaluationException {
        SpelNodeImpl leftOp = getLeftOperand();
        SpelNodeImpl rightOp = getRightOperand();

        Object leftOperand = leftOp.getValueInternal(state).getValue();
        Object rightOperand = rightOp.getValueInternal(state).getValue();

        if (leftOperand instanceof Number && rightOperand instanceof Number) {
            Number leftNumber = (Number) leftOperand;
            Number rightNumber = (Number) rightOperand;

            if (leftNumber instanceof BigDecimal) {
                BigDecimal leftBigDecimal = NumberUtils.convertNumberToTargetClass(leftNumber, BigDecimal.class);
                return new TypedValue(leftBigDecimal.pow(rightNumber.intValue()));
            } else if (leftNumber instanceof BigInteger) {
                BigInteger leftBigInteger = NumberUtils.convertNumberToTargetClass(leftNumber, BigInteger.class);
                return new TypedValue(leftBigInteger.pow(rightNumber.intValue()));
            } else if (leftNumber instanceof Double || rightNumber instanceof Double) {
                return new TypedValue(Math.pow(leftNumber.doubleValue(), rightNumber.doubleValue()));
            } else if (leftNumber instanceof Float || rightNumber instanceof Float) {
                return new TypedValue(Math.pow(leftNumber.floatValue(), rightNumber.floatValue()));
            }

            double d = Math.pow(leftNumber.doubleValue(), rightNumber.doubleValue());
            if (d > Integer.MAX_VALUE || leftNumber instanceof Long || rightNumber instanceof Long) {
                return new TypedValue((long) d);
            } else {
                return new TypedValue((int) d);
            }
        }

        return state.operate(Operation.POWER, leftOperand, rightOperand);
    }

}
